PECM Disc Flange Tooling for Scallops and Fastening Holes
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Solution Overview
Problem
The production of turbine disc clamps requires multiple machining operations, leading to mechanical stress, deformations, and increased cycle time, particularly during drilling of small-thickness disc clamps, and existing tools are not suitable for simultaneously producing scallops and fastening holes efficiently.
Innovation Solution
A tooling system for electrochemical machining with a die-sinking tool featuring coaxial conductive cathodes and an insulating body, where the first cathode has radial machining protrusions for scallops and the second cathode has axial machining nozzles for fastening holes, allowing simultaneous machining of both features using pulsed electrochemical machining.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple machining operations (broaching, milling, deburring, radiusing) are used to produce turbine disc clamps, then the geometric tolerances can be maintained, but the cycle time increases significantly and mechanical stress causes deformations
Solution Approach 1:
The patent combines multiple machining operations (scallop formation and fastening hole drilling) into a single PECM operation using a die-sinking tool with multiple cathodes. The tool simultaneously machines both scallops and fastening holes in one pass, eliminating the need for separate broaching, milling, and drilling operations, thereby dramatically reducing cycle time while maintaining geometric tolerances through controlled electrochemical material removal
Solution Approach 2:
The patent replaces traditional mechanical machining operations (broaching, milling, drilling) with pulsed electrochemical machining (PECM). This substitution eliminates mechanical contact between cutting tools and the workpiece, avoiding mechanical stress and deformations while achieving precise geometric tolerances through electrochemical material dissolution controlled by electrical parameters
2Ease of manufacture
If traditional drilling is used for fastening holes in small-thickness disc clamps, then the holes can be produced, but mechanical stress from cutting forces induces deformations
Solution Approach 1:
The patent replaces mechanical drilling with electrochemical machining using a die-sinking tool with axial machining nozzles. The PECM process removes material through electrochemical dissolution rather than mechanical cutting forces, eliminating stress-induced deformations in small-thickness disc clamps while efficiently producing accurately positioned fastening holes
3Device complexity
If a simple tooling is used for PECM, then the cost is reduced and operation is simplified, but existing tools cannot simultaneously produce scallops and fastening holes
Solution Approach 1:
The patent creates a universal die-sinking tool capable of performing multiple functions: forming scallops on the outer periphery and drilling fastening holes on the same circumference. The tool integrates multiple cathodes (first annular cathode for scallops, second cathode for fastening holes) into a single PECM device, enabling simultaneous machining of both features in one operation without requiring separate tools or multiple passes
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach eliminates mechanical stress, achieves natural radiusing, and reduces cycle time by enabling the simultaneous production of scallops and fastening holes with minimal manual finishing, maintaining geometric tolerances and avoiding burrs.
Implementation Method 1
producing scallops and fastening holes of a clamp of a disc by pulsed electrochemical machining
Implementation Method 2
absence of mechanical stress due to anodic oxidation of the material
Data Source
AI summary
Tooling for producing scallops and fastening holes of a clamp of a disc by electrochemical machining using an electrolyte, the tooling having: an annular support tray to receive the disc; lower and upper shields configured to protect the disc from splashes of the electrolyte; a clamping lock to hold the disc in position during machining; and a die-sinking tool having in a substantially cylindrical insulating body a first and a second coaxial conductive cathode, the first and second cathodes rigidly fastened to each other, the first annular cathode including at an external periphery a plurality of radial machining protrusions of a shape complementary to that of the scallops to be machined and the second cathode includes, on the same circumference external to the first cathode relative to the central axis of the disc, a plurality of axial machining nozzles of a shape similar to the fastening holes to be machined.